1. Field of the Invention
The present invention pertains to an improvement in a remote-control device for marine propulsion units and, more particularly, a remote-control device which simplifies making fine throttle adjustments and finding a neutral shift position.
2. Discussion of the Prior Art
Most marine outboard or stern drive marine propulsion units known in the art can be operated remotely, by a remote-control device. Such remote-control devices generally consist of one remote-control lever positioned near an operator's seat for both shifting and throttle operations. Such remote-control devices have a shift range (a range on either side of a central position of the lever) corresponding to a position in which a throttle valve of the marine propulsion unit would be maintained in a fully closed (idle state) position. In these arrangements, drive shifting operations can only be performed when the remote-control lever is positioned in this shift range. After the remote-control lever is shifted out of the shift range to a throttle range, the propulsion direction would be established and maintained while only the throttle valve would be opened and closed (controllable from a fully closed to a fully open position).
The compact nature of the remote-control devices of the prior are limits the permissible operating range of the remote-control levers. Therefore, in designing this control, a rather large lever movement range had to be included for both the shift range and the throttle range. However, during trolling and other low speed operations, there is a need for fine throttle adjustments. This need has been met in the prior art by using a broad throttle range. To accomplish this, however, the shift range would have to be made smaller, which makes it difficult to readily locate the neutral position midway where shifting operations can be performed. On the other hand, in order to facilitate locating the neutral position, it is desirable to enlarge the shift range. If the shift range is broadened by decreasing the throttle range, then it becomes more difficult to make fine throttle adjustments while trolling or operating at low speeds. The reason for this is that the throttle must be controlled from a fully closed to a fully open position within a very narrow throttle lever movement range. Thus, a balance must be reached in such prior art remote-control devices between enhancing the ability to find the neutral position and enabling fine throttle adjusments.